This invention relates to a lifting device for containers or the like which usually are parallelepiped and in certain cases are designed according to international standards.
The use of such containers for transporting goods of many kinds has during the last few years increased to an especially high degree. The handling of containers at goods depots, ports, etc. has increased to a corresponding degree.
The handling of containers or other unit loads takes place in several ways, depending on several factors, for example the conditions at the port and the type of ship. Also the extent of the move is an influence.
When a fork lift truck is used, as is usual, the container is provided in connection to its bottom, with tunnels for the forks. Top lift or side lift frames also are used, and a locking of the lift frame to the container proper often is effected by means of hydraulics, which is an expensive solution, because it requires an external power source and can be less attractive from a safety point of view.
For transport, cranes of different types can be used, for example when movement from a quay to the hold of a ship is concerned. The coupling between the crane and container then is effected by ropes, wires or the like provided with hooks. Cranes of a gripper type are also used. All the different methods of crane lifting have in common that the coupling operation involves manual movements. The same, of course, also applies to the uncoupling between the crane and container. At many handling places, for obvious reasons, the manual work also is risky to some extent.
There is, thus, a great need for a well-operating lifting device, which permits automatic coupling and uncoupling between crane and container or between fork lift truck with lift frame and container. The present invention relates to a lifting device of the aforesaid kind. In the case of fork lift truck, the invention implies that coupling and uncoupling can take place without requiring an external power source, at the same time the lifting device is highly satisfactory from a safety point of view. In the case of a crane, substantially all of the manual movements of coupling and uncoupling are eliminated, which is desirable from a safety point of view, and further, reduces labor demand and thereby the handling costs.
A further advantage of the lifting device according to the present invention is that it can be used with a container design, which is not changed compared with that of to-day. This design must be regarded as a substantially absolute requirement, because the design of containers to-day is highly standardized. This applies especially to so-called ISO-containers, which are designed according to international standards, are used for international transport and are exchanged between different countries.
A lifting device for the purpose here concerned further must meet high requirements of operational safety and at the same time the need for maintenance shall be small. A lifting device according to the present invention can be expected to be very safe in operation and requires maintenance to a very limited extent.
The present invention, thus, relates to a lifting device for a container or the like.